%I #19 Feb 20 2022 11:00:08
%S 1,1,1,3,1,5,3,1,1,1,1,1,1,1,7,15,1,1,3,1,5,1,11,1,1,1,1,3,7,1,15,1,1,
%T 1,1,1,1,1,1,39,1,1,21,1,1,5,1,1,1,1,1,3,13,1,3,55,7,1,1,1,5,1,1,21,1,
%U 1,3,1,17,1,5,1,1,1,1,3,1,7,3,1,1,1,1,1,1,85,1,3,11,1,3,7,1,1,1,5,1,1,1,3,5,1,51,1,13,7
%N a(n) = gcd(n, A019565(n)).
%H Antti Karttunen, <a href="/A351556/b351556.txt">Table of n, a(n) for n = 0..65537</a>
%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F a(n) = gcd(n, A019565(n)) = gcd(A007947(n), A019565(n)).
%F a(n) = A007947(a(n)).
%F a(n) = A019565(A351558(n)).
%t Table[GCD[n, Times @@ Prime@ Flatten@ Position[Reverse@ IntegerDigits[n, 2], 1]], {n, 0, 105}] (* _Michael De Vlieger_, Feb 20 2022 *)
%o (PARI)
%o A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
%o A351556(n) = gcd(n, A019565(n));
%Y Cf. A007947, A019565.
%Y Cf. also A324198, A351549, A351557, A351558.
%K nonn,look
%O 0,4
%A _Antti Karttunen_, Feb 19 2022